alistair23-linux/init/initramfs.c
Alain Knaff 30d65dbfe3 bzip2/lzma: config and initramfs support for bzip2/lzma decompression
Impact: New code for initramfs decompression, new features

This is the second part of the bzip2/lzma patch

The bzip patch is based on an idea by Christian Ludwig, includes support for
compressing the kernel with bzip2 or lzma rather than gzip. Both
compressors give smaller sizes than gzip.  Lzma's decompresses faster
than bzip2.

It also supports ramdisks and initramfs' compressed using these two
compressors.

The functionality has been successfully used for a couple of years by
the udpcast project

This version applies to "tip" kernel 2.6.28

This part contains:
- support for new compressions (bzip2 and lzma) in initramfs and
old-style ramdisk
- config dialog for kernel compression (but new kernel compressions
not yet supported)

Signed-off-by: Alain Knaff <alain@knaff.lu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-01-04 15:53:35 -08:00

577 lines
12 KiB
C

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/syscalls.h>
#include <linux/utime.h>
static __initdata char *message;
static void __init error(char *x)
{
if (!message)
message = x;
}
/* link hash */
#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
static __initdata struct hash {
int ino, minor, major;
mode_t mode;
struct hash *next;
char name[N_ALIGN(PATH_MAX)];
} *head[32];
static inline int hash(int major, int minor, int ino)
{
unsigned long tmp = ino + minor + (major << 3);
tmp += tmp >> 5;
return tmp & 31;
}
static char __init *find_link(int major, int minor, int ino,
mode_t mode, char *name)
{
struct hash **p, *q;
for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
if ((*p)->ino != ino)
continue;
if ((*p)->minor != minor)
continue;
if ((*p)->major != major)
continue;
if (((*p)->mode ^ mode) & S_IFMT)
continue;
return (*p)->name;
}
q = kmalloc(sizeof(struct hash), GFP_KERNEL);
if (!q)
panic("can't allocate link hash entry");
q->major = major;
q->minor = minor;
q->ino = ino;
q->mode = mode;
strcpy(q->name, name);
q->next = NULL;
*p = q;
return NULL;
}
static void __init free_hash(void)
{
struct hash **p, *q;
for (p = head; p < head + 32; p++) {
while (*p) {
q = *p;
*p = q->next;
kfree(q);
}
}
}
static long __init do_utime(char __user *filename, time_t mtime)
{
struct timespec t[2];
t[0].tv_sec = mtime;
t[0].tv_nsec = 0;
t[1].tv_sec = mtime;
t[1].tv_nsec = 0;
return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
}
static __initdata LIST_HEAD(dir_list);
struct dir_entry {
struct list_head list;
char *name;
time_t mtime;
};
static void __init dir_add(const char *name, time_t mtime)
{
struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
if (!de)
panic("can't allocate dir_entry buffer");
INIT_LIST_HEAD(&de->list);
de->name = kstrdup(name, GFP_KERNEL);
de->mtime = mtime;
list_add(&de->list, &dir_list);
}
static void __init dir_utime(void)
{
struct dir_entry *de, *tmp;
list_for_each_entry_safe(de, tmp, &dir_list, list) {
list_del(&de->list);
do_utime(de->name, de->mtime);
kfree(de->name);
kfree(de);
}
}
static __initdata time_t mtime;
/* cpio header parsing */
static __initdata unsigned long ino, major, minor, nlink;
static __initdata mode_t mode;
static __initdata unsigned long body_len, name_len;
static __initdata uid_t uid;
static __initdata gid_t gid;
static __initdata unsigned rdev;
static void __init parse_header(char *s)
{
unsigned long parsed[12];
char buf[9];
int i;
buf[8] = '\0';
for (i = 0, s += 6; i < 12; i++, s += 8) {
memcpy(buf, s, 8);
parsed[i] = simple_strtoul(buf, NULL, 16);
}
ino = parsed[0];
mode = parsed[1];
uid = parsed[2];
gid = parsed[3];
nlink = parsed[4];
mtime = parsed[5];
body_len = parsed[6];
major = parsed[7];
minor = parsed[8];
rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
name_len = parsed[11];
}
/* FSM */
static __initdata enum state {
Start,
Collect,
GotHeader,
SkipIt,
GotName,
CopyFile,
GotSymlink,
Reset
} state, next_state;
static __initdata char *victim;
static __initdata unsigned count;
static __initdata loff_t this_header, next_header;
static __initdata int dry_run;
static inline void __init eat(unsigned n)
{
victim += n;
this_header += n;
count -= n;
}
static __initdata char *vcollected;
static __initdata char *collected;
static __initdata int remains;
static __initdata char *collect;
static void __init read_into(char *buf, unsigned size, enum state next)
{
if (count >= size) {
collected = victim;
eat(size);
state = next;
} else {
collect = collected = buf;
remains = size;
next_state = next;
state = Collect;
}
}
static __initdata char *header_buf, *symlink_buf, *name_buf;
static int __init do_start(void)
{
read_into(header_buf, 110, GotHeader);
return 0;
}
static int __init do_collect(void)
{
unsigned n = remains;
if (count < n)
n = count;
memcpy(collect, victim, n);
eat(n);
collect += n;
if ((remains -= n) != 0)
return 1;
state = next_state;
return 0;
}
static int __init do_header(void)
{
if (memcmp(collected, "070707", 6)==0) {
error("incorrect cpio method used: use -H newc option");
return 1;
}
if (memcmp(collected, "070701", 6)) {
error("no cpio magic");
return 1;
}
parse_header(collected);
next_header = this_header + N_ALIGN(name_len) + body_len;
next_header = (next_header + 3) & ~3;
if (dry_run) {
read_into(name_buf, N_ALIGN(name_len), GotName);
return 0;
}
state = SkipIt;
if (name_len <= 0 || name_len > PATH_MAX)
return 0;
if (S_ISLNK(mode)) {
if (body_len > PATH_MAX)
return 0;
collect = collected = symlink_buf;
remains = N_ALIGN(name_len) + body_len;
next_state = GotSymlink;
state = Collect;
return 0;
}
if (S_ISREG(mode) || !body_len)
read_into(name_buf, N_ALIGN(name_len), GotName);
return 0;
}
static int __init do_skip(void)
{
if (this_header + count < next_header) {
eat(count);
return 1;
} else {
eat(next_header - this_header);
state = next_state;
return 0;
}
}
static int __init do_reset(void)
{
while(count && *victim == '\0')
eat(1);
if (count && (this_header & 3))
error("broken padding");
return 1;
}
static int __init maybe_link(void)
{
if (nlink >= 2) {
char *old = find_link(major, minor, ino, mode, collected);
if (old)
return (sys_link(old, collected) < 0) ? -1 : 1;
}
return 0;
}
static void __init clean_path(char *path, mode_t mode)
{
struct stat st;
if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
if (S_ISDIR(st.st_mode))
sys_rmdir(path);
else
sys_unlink(path);
}
}
static __initdata int wfd;
static int __init do_name(void)
{
state = SkipIt;
next_state = Reset;
if (strcmp(collected, "TRAILER!!!") == 0) {
free_hash();
return 0;
}
if (dry_run)
return 0;
clean_path(collected, mode);
if (S_ISREG(mode)) {
int ml = maybe_link();
if (ml >= 0) {
int openflags = O_WRONLY|O_CREAT;
if (ml != 1)
openflags |= O_TRUNC;
wfd = sys_open(collected, openflags, mode);
if (wfd >= 0) {
sys_fchown(wfd, uid, gid);
sys_fchmod(wfd, mode);
vcollected = kstrdup(collected, GFP_KERNEL);
state = CopyFile;
}
}
} else if (S_ISDIR(mode)) {
sys_mkdir(collected, mode);
sys_chown(collected, uid, gid);
sys_chmod(collected, mode);
dir_add(collected, mtime);
} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
S_ISFIFO(mode) || S_ISSOCK(mode)) {
if (maybe_link() == 0) {
sys_mknod(collected, mode, rdev);
sys_chown(collected, uid, gid);
sys_chmod(collected, mode);
do_utime(collected, mtime);
}
}
return 0;
}
static int __init do_copy(void)
{
if (count >= body_len) {
sys_write(wfd, victim, body_len);
sys_close(wfd);
do_utime(vcollected, mtime);
kfree(vcollected);
eat(body_len);
state = SkipIt;
return 0;
} else {
sys_write(wfd, victim, count);
body_len -= count;
eat(count);
return 1;
}
}
static int __init do_symlink(void)
{
collected[N_ALIGN(name_len) + body_len] = '\0';
clean_path(collected, 0);
sys_symlink(collected + N_ALIGN(name_len), collected);
sys_lchown(collected, uid, gid);
do_utime(collected, mtime);
state = SkipIt;
next_state = Reset;
return 0;
}
static __initdata int (*actions[])(void) = {
[Start] = do_start,
[Collect] = do_collect,
[GotHeader] = do_header,
[SkipIt] = do_skip,
[GotName] = do_name,
[CopyFile] = do_copy,
[GotSymlink] = do_symlink,
[Reset] = do_reset,
};
static int __init write_buffer(char *buf, unsigned len)
{
count = len;
victim = buf;
while (!actions[state]())
;
return len - count;
}
static int __init flush_buffer(void *bufv, unsigned len)
{
char *buf = (char *) bufv;
int written;
int origLen = len;
if (message)
return -1;
while ((written = write_buffer(buf, len)) < len && !message) {
char c = buf[written];
if (c == '0') {
buf += written;
len -= written;
state = Start;
} else if (c == 0) {
buf += written;
len -= written;
state = Reset;
} else
error("junk in compressed archive");
}
return origLen;
}
static unsigned my_inptr; /* index of next byte to be processed in inbuf */
#include <linux/decompress/bunzip2.h>
#include <linux/decompress/unlzma.h>
#include <linux/decompress/inflate.h>
static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
{
int written;
dry_run = check_only;
header_buf = kmalloc(110, GFP_KERNEL);
symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
if (!header_buf || !symlink_buf || !name_buf)
panic("can't allocate buffers");
state = Start;
this_header = 0;
message = NULL;
while (!message && len) {
loff_t saved_offset = this_header;
if (*buf == '0' && !(this_header & 3)) {
state = Start;
written = write_buffer(buf, len);
buf += written;
len -= written;
continue;
}
if (!*buf) {
buf++;
len--;
this_header++;
continue;
}
this_header = 0;
if (!gunzip(buf, len, NULL, flush_buffer, NULL,
&my_inptr, error) &&
message == NULL)
goto ok;
#ifdef CONFIG_RD_BZIP2
message = NULL; /* Zero out message, or else cpio will
think an error has already occured */
if (!bunzip2(buf, len, NULL, flush_buffer, NULL,
&my_inptr, error) &&
message == NULL) {
goto ok;
}
#endif
#ifdef CONFIG_RD_LZMA
message = NULL; /* Zero out message, or else cpio will
think an error has already occured */
if (!unlzma(buf, len, NULL, flush_buffer, NULL,
&my_inptr, error) &&
message == NULL) {
goto ok;
}
#endif
ok:
if (state != Reset)
error("junk in compressed archive");
this_header = saved_offset + my_inptr;
buf += my_inptr;
len -= my_inptr;
}
dir_utime();
kfree(name_buf);
kfree(symlink_buf);
kfree(header_buf);
return message;
}
static int __initdata do_retain_initrd;
static int __init retain_initrd_param(char *str)
{
if (*str)
return 0;
do_retain_initrd = 1;
return 1;
}
__setup("retain_initrd", retain_initrd_param);
extern char __initramfs_start[], __initramfs_end[];
#include <linux/initrd.h>
#include <linux/kexec.h>
static void __init free_initrd(void)
{
#ifdef CONFIG_KEXEC
unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
#endif
if (do_retain_initrd)
goto skip;
#ifdef CONFIG_KEXEC
/*
* If the initrd region is overlapped with crashkernel reserved region,
* free only memory that is not part of crashkernel region.
*/
if (initrd_start < crashk_end && initrd_end > crashk_start) {
/*
* Initialize initrd memory region since the kexec boot does
* not do.
*/
memset((void *)initrd_start, 0, initrd_end - initrd_start);
if (initrd_start < crashk_start)
free_initrd_mem(initrd_start, crashk_start);
if (initrd_end > crashk_end)
free_initrd_mem(crashk_end, initrd_end);
} else
#endif
free_initrd_mem(initrd_start, initrd_end);
skip:
initrd_start = 0;
initrd_end = 0;
}
static int __init populate_rootfs(void)
{
char *err = unpack_to_rootfs(__initramfs_start,
__initramfs_end - __initramfs_start, 0);
if (err)
panic(err);
if (initrd_start) {
#ifdef CONFIG_BLK_DEV_RAM
int fd;
printk(KERN_INFO "checking if image is initramfs...");
err = unpack_to_rootfs((char *)initrd_start,
initrd_end - initrd_start, 1);
if (!err) {
printk(" it is\n");
unpack_to_rootfs((char *)initrd_start,
initrd_end - initrd_start, 0);
free_initrd();
return 0;
}
printk("it isn't (%s); looks like an initrd\n", err);
fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
if (fd >= 0) {
sys_write(fd, (char *)initrd_start,
initrd_end - initrd_start);
sys_close(fd);
free_initrd();
}
#else
printk(KERN_INFO "Unpacking initramfs...");
err = unpack_to_rootfs((char *)initrd_start,
initrd_end - initrd_start, 0);
if (err)
panic(err);
printk(" done\n");
free_initrd();
#endif
}
return 0;
}
rootfs_initcall(populate_rootfs);